DewBuster™ Controller Information
The Ultimate Dew Controller
Precision temperature control keeps you dew free all night long while your telescope performs at its best. Easy to operate, stingy on power, built tough and reliable, and backed with a no-hassle 5 year warranty. Compatible with all major brands of heaters and 12VDC and 13.8VC power sources. Output configuration may be customized to your needs usually at no extra cost. Optional Heavy Duty Power Cords available.
Built To Last!
Designed for those who want the best. 15th year in production and 99% of all DewBuster™ Controllers built are still in service! RCA jacks are solidly mounted in quality aluminum case to prevent circuit board stresses when plugging in heaters. Short-protected outputs can't be harmed by heater faults. I maintain records so your receipt is not needed for the no-hassle 5-year warranty which even covers damage from home-made heater strips. And even after the warranty period your DewBuster™ Controller is repairable at a very modest cost!
Quit wasting time with your dew controller. No confusing controls to struggle with in the dark, simply turn one knob and start using your telescope! The night-vision friendly LED's blink to assure you it's working properly. No setup programming required and no need to recalibrate controller when switching temperature sensors. Color-coded outputs make connections easy.
Temperature Controlled!
Temperature Sensor measures both air and telescope temperatures and DewBuster™ Controller automatically controls heater temperature slightly above air, preventing dew while maximizing telescope performance. Swapping temperature sensors has no affect on calibration so no need to remember which sensor goes with which channel, a DewBuster™ Controller exclusive!  This also means you can order extra sensors for each of your telescopes and move the controller back and forth while never needing to recalibrate. Ambient Air Sensors are located in sensor cables to prevent errors from mounting controller on a warmer or colder surface. When used without a sensor, that channel switches to Medium Power outputs so it is not wasted.
Stingy on power!
Saves battery power by reducing heat during telescope cool-down and then applying just enough heat to prevent telescope from cooling below air temperature. Efficient Synchronized Pulse Width Modulation circuitry keeps battery voltage stable and reduces maximum current by alternating pulses between Temperature Controlled and Medium Power heaters. Low battery circuitry detects exhausted battery and gradually reduces heat  to maintain dew control as long as possible while preventing battery damage.
No Risk 30-Day Satisfaction Guarantee
If you are not satisfied with your DewBuster™ Controller for any reason you may return it for a full refund minus shipping.

  • 10 Output Jacks -- Heater Output Jacks are mounted to aluminum enclosure, not the circuit board. This prevents solder joints breaking due to stresses of plugging and unplugging heaters. Standard SCT/Refractor configuration shown above has two Temp Controlled outputs on each side, four Medium Power outputs, and two 12V Power Outlets.
  • Temperature Controlled Outputs -- With Temperature Sensor plugged in, Temp Controlled Outputs vary heater power level to control heater a few degrees F above air temperature (as set by control knob) which is ideal for corrector plate or objective lens heaters. An added bonus is that if either Temperature Sensor is not used, the Temp Controlled outputs on that side switch to Medium Power operation.
  • Medium Power Outputs -- The Medium Power outputs do not use a Temperature Sensor but instead apply a little extra power to insure dew does not form. Medium Power is typically used for small non-critical heaters such as eyepiece, finder scope, Telrad, etc.
  • 12V Power Outlets -- provide constant 12V power for accessories such as Digital Setting Circles or Cameras and remain powered even when the DewBuster™ Controller is turned off. They may also be used to provide full power to a heater if Medium Power is not enough.
  • Variety of Power Cords -- Standard cigarette plug power cord is 10-feet long and fused at 10 Amps. For observatory installations or large telescopes a Heavy Duty Power Cord is available with self-resetting PTC fuse and a wide choice of connections to fit just about any power source. For those who use multiple power sources, the Heavy Duty Powerpole® Power Cord allows quick an easy switching between "pigtails" connected to each power source.
  • Short Circuit Protected Heater Outputs -- Heater outputs are short-circuit protected so heater faults can't damage controller.
  • Synchronized Pulse Width Modulation -- For maximum efficiency Pulse Width Modulation (PWM) is used to control power to your heaters, but the DewBuster™ Controller takes it to the next level by alternating pulses between Temperature Controlled and Medium Power outputs to reduce peak current and thus fluctuations in battery voltage.
  • Customize Your Controller -- You may customize the output jack configuration or select from a variety of Power Cord Options because every DewBuster™ Controller is hand built allowing me to customize it to best suit your needs. If you need assistance do not hesitate to contact me. With a DewBuster™ Controller you are never stuck, if you ever wish to reconfigure your controller outputs or power cord then you can send it in for an upgrade and in most cases you will only pay return shipping plus the cost of the options being added. This even applies long after the warranty has expired!
  • Proven Technology -- Industrial-Spec components for dependable performance 24/7 and operation in extreme cold weather.
  • Reliability second to none -- 15th year in production and 99% of all DewBuster™ Controllers built are still in service!
  • No CCD Interference -- The DewBuster™ Controller will not interfere with CCD equipment and the 30-Day Satisfaction Guarantee allows you to return it if you are not completely satisfied.
  • Heater Status Lights -- LED's are wired directly to heater outputs so if they are illuminating then you can be sure voltage pulses are being sent to your heater. When the Temperature Controlled LED blinks you know that the temperature is being maintained at the control knob setting. Red LED's are easily visible at night yet dim enough not to interfere with your night vision.
  • Battery Status Light -- Yellow Battery warning light flickers when battery is weak, then smart Low-Battery Circuitry reduces heater power levels gradually to prevent dew as long as possible while never allowing battery to fall below 10.5V thereby preventing battery damage.
  • Premium Enclosure -- No plastic, the deluxe cast aluminum enclosure is finished in durable polyester powder coat. Durable and scratch-resistant Lexan® front panel graphics. Enclosure measures a compact 4.4" x 2.4" x 1.2".
  • Easy Removal -- Included industrial strength Velcro® strip holds tight but allows easy removal when breaking down scope.
  • Prevents overheating optics- Keeps optics slightly warmer than the air temperature, just enough to prevent dew but not so much that it prevents your telescope from performing at its best.
  • Set&Forget thermostat control- Just set the control knob at the beginning of the night and controller does the rest. In an observatory the controller may be left on 24/7 to help with daytime condensation.
  • Swapping Temperature Sensors does not affect calibration so no need to remember which sensor goes with which channel. This also means you can purchase extra sensors for a second telescope and move the controller back and forth with no fuss.
  • No drift in accuracy as temperature changes -- The DewBuster™ Controller uses dependable thermocouple technology which does not drift over wide temperature extremes allowing accurate and precise temperature control.
  • Interchangeable low cost temperature sensors - The standard model controller comes with one Temperature Sensor Cable (optional on Big Dob model) but there are two Temperature Sensor Cable input jacks so a second sensor may purchased for use with a piggybacked scope. You may also wish to purchase extra Temperature Sensor Cables if you have several telescopes and do not wish to move the sensor from scope to scope. The DewBuster™ Controller does not require recalibration when swapping sensors, a DewBuster™ Controller exclusive.
  • Temperature Sensor Cable - air and telescope temperature sensors are combined into one Temperature Sensor Cable to minimize extra wires. The standard SCT/Refractor type Temperature Sensor Cable conveniently clips under your heater strip and can easily be moved between telescopes if you wish to share your DewBuster™ among several scopes. The six foot long cable matches the cord length of most heater strips but you may specify a shorter length in comments section of order form. For applications where a heater strip is not being used, a special Newtonian type Temperature Sensor Cable is available and the tip may be attached to the mirror with epoxy or other means (CLICK HERE for more information on the Newtonian Sensor installation).
  • The DewBuster™ Controller does not come with heater strips but it is compatible with commercial 12V heaters as well as heaters built using my instructions. You may also use a mix of home-made and mixed brands of commercial heaters.
  • The DewBuster™ Controller has short-circuit protection so heater faults will not damage it and the warranty even covers damage caused by improperly constructed home-made heater strips.
  • Conserves Battery Power - Temperature control applies only as much heat as needed to replace what is being lost to the sky. You can save energy by wrapping insulation around outside of a temperature controlled objective or corrector plate heater which will reduce heat losses and the controller will automatically reduce power to the heater resulting in longer battery life.
  • Efficient - Pulse Width Modulated heater output circuitry with Power MOSFET drivers for maximum efficiency and longer battery run time.
  • Low Battery Light - yellow light flickers when battery gets below 11 VDC then brightens as battery weakens and remains on constantly when battery is exhausted.
  • Smart Low-Battery Circuitry - reduces heater power as battery becomes exhausted keeping dew heaters operational as long as possible yet preventing battery damage. Works in conjunction with Low Battery warning light so you can disconnect unnecessary items to conserve power. Provides peace of mind if you leave controller turned on when going to bed.
  • 30-Day Satisfaction Guarantee - If you are not satisfied with your DewBuster™ Controller for any reason contact me for return instructions. You will be given a full refund minus shipping.
  • No-Hassle 5-Year Warranty - Your DewBuster™ Controller is warranted to the original purchaser for a minimum of 5 years against failures of any kind including reverse power hookup and damage caused by shorted heaters of any brand including home-built heaters. I keep a record of your purchase so your receipt is not needed for warranty service. After the warranty expires, repairs will be done for a very reasonable flat-rate fee.
  • DewBuster™ Controller
  • Velcro™ mounting strip
  • Owner's Manual

NOTE: The order form defaults to one Temperature Sensor Cable which is what most users will need. You may add or delete sensors to match your needs. See instruction manual for more information.

You will also need heaters strips and a power source.


  • DewBuster™ Controllers are not sold through dealers, they are available only through this web site.
  • Each controller is custom built to order which takes about 3 weeks.
  • Prices, options, and shipping are shown on the ORDER FORM (order forms accessed via left Side Menu).
  • If you need help configuring your controller, just fill out the order form as best you can and hold off making your payment. Then contact me so that I can assist you in configuring your controller and adjust your order as necessary. I will then send you a link to make your payment if you wish to proceed.
  • International Orders Welcome!

"Big Dob" DewBuster™ Controller
  • A special DewBuster™ Controller developed in collaboration with Markless Astronomics to give Big Dob owners a dew controller with built-in power distribution rail. Unlike the standard controller, the Big Dob version does not have a power cord but receives power from the telscope wiring via an RCA Power Input jack. If you need a power cord you can order the standard DewBuster™ Controller and select a configuration with 4 power outlets.
  • The Big-Dob DewBuster™ Controller may be ordered using the BIG DOB ORDER FORM on the side menu. See the ORDER FORM for more information about the Big-Dob DewBuster™ Controller. Contact me if you have any questions about the controller or options available on the order form.
  • Contact Charlie Starks of Markless Astronomics for information about their mounting bracket, power cables, and wiring kits for a plug and play installation.